import sys
input = sys.stdin.readline

def inp():
	return(int(input()))

print("Yes" if inp() >=30 else "No") import sys sys input = sys.stdin.readline input sys.stdin.readline sys.stdin sys stdin readline def inp():
	return(int(input())) inp return(int(input())) int(input()) int input() input print("Yes" if inp() >=30 else "No") print "Yes" if inp() >=30 else "No" inp() >=30 inp() inp 30 "Yes" "No" def inp():
	return(int(input())) def inp():
	return(int(input())) inp input = sys.stdin.readline sys.stdin.readline input
import sys
input = sys.stdin.readline

def inp():
	return(int(input()))

print("Yes" if inp() >=30 else "No")